SHOW Signed

net.rim.device.api.crypto
Class XDecryptorEngine

java.lang.Object
  |
  +--net.rim.device.api.crypto.XDecryptorEngine
All Implemented Interfaces:
BlockDecryptorEngine

public final class XDecryptorEngine
extends Object
implements BlockDecryptorEngine

XDecryptorEngine efficiently extends the key space of a block cipher, by whitening (ie xor'ing) random secret data before and after the cipher executes. The whitening vectors must remain secret.

    D( key, plaintext ) = D( key, ciphertext ^ postWhitening ) ^ preWhitening
 

For a code sample using the X decryptor engine, click here.

Category:
Signed: This element is only accessible by signed clients. If you intend to use this element, please contact RIM to establish the necessary agreements that will allow you to have your COD files signed. Signing is only required for use on the device, development under the JDE can occur without signing the CODs.

Since:
JDE 3.6.0
See Also:
XEncryptorEngine

Constructor Summary
 Category: Signed XDecryptorEngine(BlockDecryptorEngine engine, InitializationVector preWhitening, InitializationVector postWhitening)
          Creates an XDecryptorEngine object with the given algorithm engine and whitening vectors.
 
Method Summary
 Category: Signed  void decrypt(byte[] ciphertext, int ciphertextOffset, byte[] plaintext, int plaintextOffset)
          Decodes a block of the given ciphertext into a block of plaintext.
 Category: Signed  String getAlgorithm()
          Returns the name of the encryption algorithm used, ie BlockDecryptorEngine.getAlgorithm() + "/X".
 Category: Signed  int getBlockLength()
          Returns the block length of the block cipher in bytes.
 Category: Signed  InitializationVector getPostWhitening()
          Returns the whitening vector that is applied to the ciphertext.
 Category: Signed  InitializationVector getPreWhitening()
          Returns the whitening vector that is applied to the plaintext.
 Category: Signed  void setWhiteningVectors(InitializationVector preWhitening, InitializationVector postWhitening)
          Sets the pre and post whitening vectors.
 
Methods inherited from class java.lang.Object
equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

XDecryptorEngine

public XDecryptorEngine(BlockDecryptorEngine engine,
                        InitializationVector preWhitening,
                        InitializationVector postWhitening)
Creates an XDecryptorEngine object with the given algorithm engine and whitening vectors.

Parameters:
engine - The algorithm engine used for decryption.
preWhitening - The whitening vector that is applied to the plaintext. This should remain secret. These must not be null.
postWhitening - The whitening vector that is applied to the ciphertext. This should remain secret. These must not be null.
Since:
JDE 3.6.0
Category:
Signed: This element is only accessible by signed clients. If you intend to use this element, please contact RIM to establish the necessary agreements that will allow you to have your COD files signed. Signing is only required for use on the device, development under the JDE can occur without signing the CODs.
Method Detail

getAlgorithm

public String getAlgorithm()
Returns the name of the encryption algorithm used, ie BlockDecryptorEngine.getAlgorithm() + "/X".

Returns:
A String that represents the name of the alorithm.
Since:
JDE 3.6.0
Category:
Signed: This element is only accessible by signed clients. If you intend to use this element, please contact RIM to establish the necessary agreements that will allow you to have your COD files signed. Signing is only required for use on the device, development under the JDE can occur without signing the CODs.

getBlockLength

public int getBlockLength()
Description copied from interface: BlockDecryptorEngine
Returns the block length of the block cipher in bytes.

Since:
JDE 3.6.0
Category:
Signed: This element is only accessible by signed clients. If you intend to use this element, please contact RIM to establish the necessary agreements that will allow you to have your COD files signed. Signing is only required for use on the device, development under the JDE can occur without signing the CODs.

setWhiteningVectors

public void setWhiteningVectors(InitializationVector preWhitening,
                                InitializationVector postWhitening)
Sets the pre and post whitening vectors.
Parameters:
preWhitening - The whitening vector that is applied to the plaintext. This should remain secret.
postWhitening - The whitening vector that is applied to the ciphertext. This should remain secret.
Since:
JDE 4.0.2
Category:
Signed: This element is only accessible by signed clients. If you intend to use this element, please contact RIM to establish the necessary agreements that will allow you to have your COD files signed. Signing is only required for use on the device, development under the JDE can occur without signing the CODs.

getPreWhitening

public InitializationVector getPreWhitening()
Returns the whitening vector that is applied to the plaintext.

Returns:
An initialization vector that represents the whitening.
Since:
JDE 3.6.0
Category:
Signed: This element is only accessible by signed clients. If you intend to use this element, please contact RIM to establish the necessary agreements that will allow you to have your COD files signed. Signing is only required for use on the device, development under the JDE can occur without signing the CODs.

getPostWhitening

public InitializationVector getPostWhitening()
Returns the whitening vector that is applied to the ciphertext.

Returns:
An initialization vector that represents the whitening.
Since:
JDE 3.6.0
Category:
Signed: This element is only accessible by signed clients. If you intend to use this element, please contact RIM to establish the necessary agreements that will allow you to have your COD files signed. Signing is only required for use on the device, development under the JDE can occur without signing the CODs.

decrypt

public void decrypt(byte[] ciphertext,
                    int ciphertextOffset,
                    byte[] plaintext,
                    int plaintextOffset)
             throws CryptoTokenException
Description copied from interface: BlockDecryptorEngine
Decodes a block of the given ciphertext into a block of plaintext.

Since:
JDE 4.0.2
Category:
Signed: This element is only accessible by signed clients. If you intend to use this element, please contact RIM to establish the necessary agreements that will allow you to have your COD files signed. Signing is only required for use on the device, development under the JDE can occur without signing the CODs.


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